Question 1 of 33

1. What is electric drive?

A machine converts mechanical energy into electrical

A device used as prime mover for generator

A device converts A.C to D.C supply

An electro mechanical device for controlling motor

Question 1 of 33

Question 2 of 33

2. What is the function of Field Supply Unit (FSU) in DC drive?

Provides a constant voltage to the armature of the motor

Provides variable voltage to the field winding of motor

Produces required firing current to the firing circuit

Provides a constant voltage to the field winding of motor

Question 2 of 33

Question 3 of 33

3. What is the purpose of LCD in Basic Operator Panel (BOP) in AC drive?

Indicate the status of drive

Indicate the incorrect operation of BOP

Indicate the display error in reading

Monitor the parameter of AC drive

Question 3 of 33

Question 4 of 33

4. What is the function of VSI drives?

Converts A.C to A.C

Converts D.C to D.C

Converts D.C to A.C

Converts A.C to D.C

Question 4 of 33

Question 5 of 33

5. How can constant torque be obtained from armature and field controlled drives?

By reducing the field current

By controlling the armature voltage

By increasing the field current

By reducing the armature current

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Question 6 of 33

6. Which is the application of single quadrant loads operating in first quadrant in drives?

Conveyors

Centrifugal pumps

Elevators

Hoists

Question 6 of 33

Question 7 of 33

7. Which control system is used for Eddy current drives?

AC voltage controller

DC chopper controller

Slip controller

Rectifier controller

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Question 8 of 33

8. What is IGBT in VF drive?

Field supply switching device

Rectifier switching device

D.C bus switching device

Inverter switching device

Question 8 of 33

Question 9 of 33

9. What is the full form of B.O.P in D.C drive?

Basic Operational Panel

Basic Operation Programme

Bridge Operator Programme

Bridge Operation Panel

Question 9 of 33

Question 10 of 33

10. Which is the correct sequence operation of key button in BOP of AC drive to change the direction of rotation?

Press OFF → REV → ON

Press ON → REV → ON

Press ON → REV → OFF → ON

Press ON → OFF → REV → ON

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Question 11 of 33

11. What is the disadvantage of DC drive?

More expensive than AC drive for high capacity motor

Installation of DC drives is more complicated

Not suitable for high speed operation

More complex with a single power conversion

Question 11 of 33

Question 12 of 33

12. Why are A.C drives better suited for high speed operation?

No brushes and commutation

Robust in construction

High starting torque

Having lighter gauge winding

Question 12 of 33

Question 13 of 33

13. What is the purpose of LCD on basic operator panel in D.C drive?

Indicate the fault

Monitor the parameter

Display the speed

Display availability of supply

Question 13 of 33

Question 14 of 33

14. What is the function of IGBT in AC drive?

Smoothening incoming A.C supply

Controls the power delivered to the motor

Stabilize the output voltage from the rectifier

Converts incoming A.C power into D.C power output

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Question 15 of 33

15. What is the name of the component marked as 'X' in the block diagram of AC drive?

D.C bus

Rectifier

A.C motor

Inverter

Question 15 of 33

Question 16 of 33

16. Which type of machine in industries is provided with multi-motor electric drive?

Shearing machine

Heavy duty electric drilling machine

Rolling machine

Air Compressor

Question 16 of 33

Question 17 of 33

17. Which control system consumes very low power for motion control in AC and DC motors?

Field control

Drives control

Armature control

Voltage control

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Question 18 of 33

18. What is the purpose of PROG/DATA button in BOP of AC drive?

To display the data direction of rotation forward/REV

To change the parameter setting

To store the entered data and factory stored data

To display the data status of frequency and current

Question 18 of 33

Question 19 of 33

19. What is the function of power controller in drive circuits?

It maintain the torque at low voltage conditions

It sounds an alarm in no load conditions

It detects the overloading condition of motor

It reduce motor current during transient operation

Question 19 of 33

Question 20 of 33

20. What is the reason for using shielded cable for connecting low level signal circuits in DC drives?

Easy for connection

Protects from mechanical injuries

Eliminates the electrical interference

Good appearance

Question 20 of 33

Question 21 of 33

21. What is the purpose of JOG key in control panel of D.C drive?

Stop the motor

Reverse the direction of motor

Inching operation

Restart the motor

Question 21 of 33

Question 22 of 33

22. What is the advantage of AC drive compared to DC drive?

Installation and running cost is less

Requires less space

Power circuit and control circuits are simple

Fast response and wide speed range of control

Question 22 of 33

Question 23 of 33

23. How can the base speed of D.C shunt motor be increased by using D.C drive?

By reducing the armature voltage

By reducing the field current

By increasing the supply voltage

By increasing the field current

Question 23 of 33

Question 24 of 33

24. Which is the classification of drive according to dynamics and transients?

Automatic control drive

Variable position control drive

Intermittent duty drive

Short time duty drive

Question 24 of 33

Question 25 of 33

25. Which drive is classified according to mode of operation?

Group drive

Manual drive

Continuous duty drive

Individual drive

Question 25 of 33

Question 26 of 33

26. Which device controls the speed of A.C motor in A.C drive?

Field supply unit (FSU)

COMMS technology box

Microprocessor based electronic device

Speed feedback technology box

Question 26 of 33

Question 27 of 33

27. What is the main use of A.C drive?

Control stepless speed in motors

High starting torque

Interlocking system in industries

Group drive motors

Question 27 of 33

Question 28 of 33

28. Which is proportional to the torque in D.C motor?

Armature current

Terminal voltage

Field current

Back e.m.f

Question 28 of 33

Question 29 of 33

29. Why are A.C drives mostly used in process plants?

Easy to operate

Maintenance free long life

Very high starting torque

Robust in construction

Question 29 of 33

Question 30 of 33

30. Which type of sensing unit is employed in drive systems?

Speed sensing

Opto coupler

Resistance temperature detector

Photo voltaic cell

Question 30 of 33

Question 31 of 33

31. Which power modulator is used in the electric drive system?

Phase sequence indicator

Frequency multiplier

Servo controlled voltage stabilizer

Cyclo converters

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Question 32 of 33

32. What is the name of the characteristic curve in D.C drive?

Torque Vs field current characteristic

Field current Vs armature current characteristic

Speed Vs torque characteristic

Speed Vs armature current characteristic

Question 32 of 33

Question 33 of 33

33. Why is it necessary to keep V/F ratio constant in a drive?

Maintain the rated torque at all speeds

Maintain the speed of motor constant

Maintain the rotor current minimum

Keep the stator flux maximum

Question 33 of 33